<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title></title>
    <style media="screen">
    * {margin:0; padding:0; list-style: none;}
    ul {overflow:hidden;}
    ul li {width:20%; float:left; box-sizing:border-box; border:5px solid black; padding:10px;}
    </style>
  </head>
  <body>
    <ul>
      <li>aaa</li>
      <li>bbb</li>
      <li>ccc</li>
      <li>ddd</li>
      <li>eee</li>
    </ul>
  </body>
</html>
